NOTE: By "description box", I mean the yellow box that appears when you are editing an option on your CV. The contents of the box explain the option that you are editing.
Normally, all of the editable options on the "Edit CV" page on Careers have description boxes appear when you begin editing. However, this is not the case for the "What Type of Work are You Seeking?" option. I noticed that the only way to make the description box appear is by clicking Tab from the option above ("Background").
I'm not sure if this is a bug or not, but it contradicts the norm that is expressed by the design of the rest of the options on the page.